Refrigerating apparatus



y 1937. A. A. KUCHER 2,080,358

REFRIGERATING APPARATUS Filed Dec. 29. 1954 INVEN TOR.

ATTORNEY.

Patented May 11, 1937 UNITED STATES PATENT OFFICE REFRIGERATING APPARATUS Andrew A. Kucher, Dayton, Ohio, assig'nor to General Motors Corporation, Dayton, Ohio, a corporation of Delaware A Application December 29, 1934, Serial No. 759,756

11 Claims. (Cl. 8 2-115) This invention relates to refrigerating apparatus and more particularly to a novel system and control therefor for automatically varying the refrigeration output of the apparatus.

Heretofore in the construction of refrigerators, particularly those comprising a cabinet having a. food storage compartment and which are intended principally for household use, in meeting the problem of varying the refrigeration output of the machine to provide substantially constant food preserving temperatures in the cabinet, it

has been customary to provide an automatic switch for stopping and starting the refrigerant liquefying unit as by controlling the motor which drives the compressor and to thus operate the apparatus intermittently. With such a method of control, the system, while it is operating, produces refrigeration at a substantially constant rate and the variation in average amount of 2 refrigerant produced over a given period results in variations in the lengths of the period during which the machine operates or is idle. A refrigerating apparatus of this character has certain disadvantages, among them being high first cost and. frequent, service difflculties, together with certain difficulties arising from the con tinued stopping and starting of the refrigerant liquefying unit, particularly with liquefying units of the compression type.

It is an object, therefore, of the present invention to provide a refrigerating apparatus which is readily adapted to extremely low cost production and in which the difliculties inherent in an intermittently operated refrigerator are avoided.

It is a further object of the invention to provide a refrigerating apparatus in which automatic control of the output of the apparatus is attained while the refrigerant liqueiyin'g unit is' constantly running.

It is also an object of the invention to provide a refrigerating apparatus in which the liquefying unit runs continuously throughout a substantial range of room temperatures normally encountered and in which substantially constant temperatures are maintained in the food preserving or other compartment to be cooled solely by purposely causing the refrigerating system to operate at reduced eificiencies when its full capacity is not required.

Another object is to provide a refrigerating apparatus in which heat exchange between the evaporating refrigerant and the condensing refrigerant may be established by means of a thermostatically controlled bypass in the refrigerant circuit.

Further objects and advantages of the present invention will be apparent from the following description, reference being had to the accompanying drawing in which a preferred form of I the present invention is clearly shown. 5

In the drawing:

Referring now to the drawing, Fig. 1 illustrates a diagrammatic view of a refrigerating apparatus embodying the present invention, a portion of the mechanism being shown in cross 10 section.

Fig. 2 is a view corresponding to Fig. 1 of a modified form of the invention.

In the form of the invention illustrated in Fig.

1, there is provided a refrigerator cabinet indi- 5 cated diagrammatically at Ill having a food compartment l2 in which substantially constant temperatures are to be maintained throughout a wide range of room temperatures. For example, in an ordinary household refrigerator, it is 20 desirable to maintain a temperature within the compartment l2 between substantially 42 and 50 F., while room temperatures may run as high as 110 F. and are generally not below 60 F. Associated with the cabinet in is a refrigerant liquefying unit comprising a compressor I4, and a condenser i6, both of which may take any of numerous suitable forms in order to maintain a constant supply of liquefied refrigerant for use in the system. Within the compartment l2, there is mounted a refrigerant evaporator l8 for cooling the air within the compartment l2, and which may also be provided with means for freezing water as is well known in the art. Suitable means for controlling the flow of liquid refrigerant from the liquefying unit to the evaporator are provided and may comprise an expansion valve or other refrigerant control device 20. The elements so far described are connected in series by suitable refrigerant conduits in the well known manner to provide a closed refrigerant circuit. The elements of the refrigerating system including the refrigerant liquefying unit,

the liquid refrigerant control device and the evaporator are preferably so proportioned and coordinated with each other as to provide a maximum refrigeration output not substantially in excess of the heat load requirements of the cabinet under the highest room temperature normally encountered.

In order to provide for a reduction in the output of the apparatus under conditions at which its maximum output is not required, means are provided for purposely causing the system to operate at reduced emciencies. Generally speaking, this means has for its purpose the introduction of hot compressed refrigerant into the heat exchange relation with vaporizing refrigerant so that a portion of the energy input to the system is wasted. In the form of the invention shown in Fig. 1, a valve 22 is provided in the refrigerant conduit connecting the compressor to the condenser. The valve 22 is constructed so as to alternatively connect the discharge from the compressor either to the condenser IE or to a bypass conduit 24 having a portion 26 in heat exchange relation to the evaporator i8 and communicating with the conduit connecting the outlet of the condenser with the expansion valve 20. The valve 22 is operated by means of a bellows 28 which expands and contracts in accordance with the temperatures of a thermostatic bulb 30 situated within the food compartment l2.

In operation of the apparatus, whenever current is fed to the motor-compressor unit H, the

refrigerant liquefying unit comprising the compressor i4 and the condenser IE will remain in operation regardless of the load requirements of the evaporator l8. Refrigerant is compressed in the compressor I4 and delivered to the condenser [G where it is condensed to be expanded through the expansion valve 20 and vaporized in the evaporator l8. When the temperature within the compartment i 2 is below the maximum desirable temperature, the thermostatic valve 22 is moved to the position illustrated in Fig. 1 by the contraction of the bellows 28. In this position, the refrigerant discharged from the compressor I4 is fed through the bypass' 24-26 to the expansion valve 20. Due to the fact that heat of vaporization absorbed by the evaporator i8 is taken up from the refrigerant condensing in the heat exchange portion 26, the system operates at a very low efficiency, thus reducing the output of the system when its full capacity is not required to maintain the compartment I 2 at the desired temperature. When the full capacity of the apparatus is required, the bellows 28 will expand due to the higher temperature in compartment l2 and connect the outlet of the compressor i4 directly to the condenser l6 as well as close off communication to the bypass 24-26.

Various intermediate positions between the two extremes described may be taken by the valve 22 and thus the output of the apparatus may be automatically varied to correspond to the requirements at the food compartment l2.

In the modification of the invention shown in Fig. 2, similar results are achieved by means of a thermostatic valve 32 controlling a bypass conduit 34 connecting the inlet of the evaporator with a heat exchanger 36 positioned between the compressor and the condenser. The thermostatic valve 32 is illustrated as one of the snap acting type comprising a bellows 38 responsive to the pressure of a volatile fiuid in the thermostatic bulb 40. The bellows 38 operates a valve plunger 42 through the medium of a snap' acting linkage 44.

In operation, whenever the refrigeration requirements in the food compartment i 2 are less than the maximum capacity of the apparatus, the bellows will contract, causing valve 42 to open and permit some of the refrigerant passing the expansion valve 20 to pass to the inlet of the compressor through the heat exchanger 36. In this way, a portion of the expanding refrigerant is caused to absorb heat from the refrigerant to be liquefied and the efliciency of operation of the apparatus is thus temporarily reduced in order 1 of the liquefying unit below any desired room temperature less than maximum. I Thus, the present invention provides a refrig crating apparatus having means for maintaining the temperature of thecompartment to be cooled within a predeterminedrange, while the refrigerating apparatus for the compartment is maintained in continuous operation.

While the form of embodiment of the invention as herein disclosed constitutes a preferred form, it is to be understood that other forms might be adopted, all coming within the scope of the claims which follow.

What is claimed is as follows:

1. A refrigerating apparatus comprising in combination a cabinet to be cooled, refrigerant liquefying means, and a refrigerant evaporator, coordinated with each other to provide a capacity not substantially in excess of the heat load of the cabinet under the highest room temperature normally encountered, and means for regulating cabinet temperatures by an interchange of heat between the evaporating refrigerant and the liquefying refrigerant, said last mentioned means including a heat exchange device forming a portion of a bypass extending around the evaporator for liquefying refrigerant by giving up heat therefrom directly to evaporating refrigerant.

2. A refrigerating apparatus comprising in combination a cabinet to be cooled, refrigerant liquefying means, and a refrigerant evaporator,

coordinated with each other to provide a capacity not substantially in excess of the heat load of the cabinet under the highest room temperature normally encountered, and means for regulating cabinet temperatures by an interchange of heat between the evaporating refrigerant and the liquefying refrigerant, said last mentioned means including a heat exchange device forming a portion of a bypass extending around the evaporator for liquefying refrigerant by giving up heat therefrom directly to evaporating refrigerant, and a thermostatic valve for controlling the delivery of refrigerant to said heat exchange device.

3. A refrigerating apparatus comprising in combination a cabinet to be cooled, refrigerant liquefying means, and a refrigerant evaporator, coordinated with each other to provide a capacity not substantially in excess of the heat load of the cabinet under the highest room temperature normally encountered, and means for regulating cabinet temperatures by an interchange of heat between the evaporating refrigerant and the liquefying refrigerant, said last mentioned means including a bypass extending around the evaporator for bringing expanding and liquefying refrigerant into heat interchanging relation.

4. A refrigerating apparatus comprising in combination a cabinet to be cooled, refrigerant liquefying means, and a. refrigerant evaporator, coordinated with each other to provide a capacevaporator for bringing expanding and liquefying refrigerant into heat interchanging relation, and a thermostatic valve for controlling the delivery of refrigerant through said bypass.

5. A refrigerating apparatus comprising in combination a cabinet to be cooled, refrigerant liquefying means, and a refrigerant evaporator, coordinated with each other to provide a capacity not substantially in excess of the heat load of the cabinet under the highest room temperature normally encountered, and means for regulating cabinet temperatures by an' interchange of heat between the evaporating refrigerant and the liquefying refrigerant, said last mentioned means including a heat exchanger at the evaporator but separate from the evaporator, said heat exchanger forming a portion of a bypass around a unit of the liquefying means and thermostatic means for controlling the delivery of refrigerant to be liquefied to said heat exchanger.

6. A refrigerating apparatus comprising in combination a cabinet to be cooled, refrigerant liquefying means, and a refrigerant evaporator, coordinated with each other to provide a capacity not substantially in excess of the heat load of the cabinet under the highest room temperature normally encountered, and means for regulating cabinet temperatures by an interchange of heat between the evaporating refrigerant and the liquefying refrigerant, said last mentioned means including a heat exchanger at the liquefying means said heat exchanger forming a portion of the bypass around the evaporator, and thermostatic means for controlling the delivery of refrigerant to be evaporated to said heat exchanger.

7. Refrigerating apparatus including refrigerant compressor and a heat transfer means for liquefying the refrigerant, a second heat transfer means connected to the first mentioned heat transfer means and the compressor for evaporating refrigerant, a bypass around one of said heat transfer means, said bypass including an intermediate portion providing a heat exchange between the liquefylng refrigerant and the evaporating refrigerant.

8. Refrigerating apparatus including refrigerant compressor and a heat transfer means for liquefying the refrigerant, a second heat transfer means connected to the first mentioned heat transfer means and the compressor for evaporating refrigerant, a bypass around one of said heat transfer means, said bypass including an intermediate portion providing a heat exchange between the liquefying refrigerant and the evaporating refrigerant and thermostatic means for controlling the flow of refrigerant through said bypass.

9. Refrigerating apparatus including refrigerant compressor and a heat transfer means for liquefying the refrigerant, a second heat transfer means connected to the first mentioned heat transfer means and the compressor for evaporating refrigerant, a bypass around one of said heat transfer means, said bypass including an intermediate portion providing a heat exchange between the liquefying refrigerant and the evaporating refrigerant and snap acting means for controlling the flow of refrigerant through said bypass.

10. Refrigerating apparatus including refrigerant compressor and a heat transfer means for liquefying the refrigerant, a second heat transfer means connected to the first mentioned heat transfer means and the compressor for evaporating refrigerant, a bypass around one of said heat transfer means, said bypass including an intermediate portion providing a heat exchange between the liquefying refrigerant and the evaporating refrigerant and pressure operated means for controlling the flow of refrigerant through said bypass.

ll. Refrigerating apparatus including refrigerant compressor and a heat transfer means for liquefying the refrigerant, a second heat transfer means connected to the first mentioned heat transfer means and the compressor for evaporating refrigerant, a bypass around one of said heat transfer means, said bypass including an intermediate portion providing a heat exchange between the liquefying refrigerant and the evaporating refrigerant and means responsive to temperatures influenced by the evaporating means for controlling the flow of refrigerant through said bypass.

ANDREW A. KUCHER. 

